Safety system for a breathing apparatus for delivering an anesthetic agent

ABSTRACT

A safety system for a breathing apparatus for delivery of an anesthetic agent having an anesthetic agent vaporizer having a reservoir for containing a liquid anesthetic agent has a reservoir for containing a liquid medical agent, a port for filling the reservoir with the liquid anesthetic agent, and a sensor device for sensing a filling action of the port. A change of position of a lid covering the port is can be detected, or insertion of a fill vessel into said the port is can be detected. Thus safety of said the equipment is improved by being able to de-pressurize the reservoir before opening a filling valve for communication of the port with the interior of the reservoir.

RELATED APPLICATION

The present application is a divisional application of U.S. patentapplication Ser. No. 12/664,414, having an official filing date of Jun.16, 2010, the content of which is incorporated herein by reference.

FIELD OF THE INVENTION

This invention pertains to the field of systems for increasing thesafety of a breathing apparatus for delivery of an anesthetic agent.More specifically, the invention relates to a system for increasing thesafety in connection with refilling a liquid anesthetic agent deliveryequipment with a liquid anesthetic agent.

DESCRIPTION OF THE PRIOR ART

A pressurized liquid anesthetic agent delivery equipment is disclosed inU.S. Pat. No. 6,878,133. The equipment includes a primary reservoir forreceiving the medical liquid to be delivered, and a secondary reservoir,fluidly connected to the primary reservoir. When the equipment is to bereplenished with liquid anesthetic agent, the secondary reservoir isdisconnected from the primary reservoir and the secondary reservoir isoperative for providing the medical fluid to the patient duringrefilling of the primary reservoir with liquid anesthetic agent. Whenthe primary reservoir is disconnected from the secondary reservoir, adriving pressure originally present in the primary reservoir is firstequilibrated to the atmospheric pressure, whereupon a liquid anestheticagent source is connected to the primary reservoir and emptied into theprimary reservoir. When the primary reservoir is sufficiently refilled,the liquid source is removed, and the driving pressure is restored inthe primary reservoir. Then the primary reservoir is reconnected to thesecondary reservoir for continued operation.

Another similar equipment is disclosed in WO 2007/006348 of the sameapplicant as the present application.

Such equipment would work well were it not for the human factor.

In order to adjust the equipment for refilling, the operator switchesone or several valves in order to equilibrate the primary reservoir. Ina typical clinical operating environment of such liquid anesthetic agentdelivery equipment, the operator may unintentionally loose the attentionof the equipment. This might lead to less desired effects. For instance,when the primary reservoir is about to be replenished with fresh liquidanesthetic agent. In case and the primary reservoir is not equilibratedto atmospheric pressure, i.e. still under pressure, before establishingfluid contact through the refill port between the primary reservoir andthe medical liquid source, e.g. a bottle with liquid anesthetic agent,the medical liquid might escape into the surrounding environment. Inextreme cases, the medical liquid may squirt or eject from the reservoiror the medical liquid source due to the overpressure thus present in thereservoir and communicated through the refill port. Inhalation ofvaporized anesthetic agent by healthcare personnel in the surroundingenvironment can cause drowsiness and may cause other health troubleswhen one is exposed to the anesthetic agent. Furthermore, certainvolatile medical liquids might be flammable at atmospheric pressure.

Thus, there is a need in the art to reduce the human factor influenceduring refilling of a medical liquid into a medical liquid deliveryequipment.

Hence, an improved medical liquid delivery equipment would beadvantageous and in particular allowing for increased patient safetyand/or operator safety.

SUMMARY OF THE INVENTION

Accordingly, embodiments of the present invention preferably seek tomitigate, alleviate or eliminate one or more deficiencies, disadvantagesor issues in the art, such as the above-identified, singly or in anycombination by providing a safety system according to the appendedpatent claims.

A safety system for a medical equipment has a reservoir for containing aliquid medical agent, a port for filling the reservoir with the liquidmedical agent, and a sensor device for sensing a filling action at theport. For instance a change of position of a lid covering the port isdetected, or insertion of a fill vessel into the port is detected. Thussafety of the equipment is improved, for instance by being able todepressurize the reservoir before opening a filling valve forcommunication of the port with the inner of the reservoir.

According to a first aspect of the invention, a safety system for abreathing apparatus for delivery of an anesthetic agent having ananesthetic vaporizer is provided that has a reservoir for containing theanesthetic agent in liquid form, and a port for filling the reservoirwith the liquid anesthetic agent, wherein the apparatus has a sensordevice for sensing a filling action of the port.

In an embodiment the safety system may be configured to arrange thebreathing apparatus for delivery of an anesthetic agent having ananesthetic vaporizer into a filling condition in dependence of a signalof the sensor device sensing the filling action of the port.

In an embodiment the reservoir may be adapted to be pressurized fordelivery of the anesthetic agent, and wherein the anesthetic agentvaporizer is an anesthetic vaporizer for pressurized anesthetic agents.

In an embodiment the control device is arranged to relieve anover-pressure prevailing in the reservoir before filling in order toarrange the breathing apparatus for delivery of an anesthetic agenthaving an anesthetic vaporizer into the filling condition.

In an embodiment, the sensing device may be arranged for sensing when aprotection member is positioned in its home position and to emit asignal when the protection member is in the home position.Alternatively, the sensing device may be arranged for sensing when theprotection member is positioned in a position, in which the port is openand free to receive a filling means, and to emit a signal when theprotection member is in the opened position. The protection member maybe a lid, which may be moveable in a linear, rotational or pivotingmovement.

In another embodiment, the sensor device may operate by means ofelectromagnetic radiation, such as ultraviolet, visible or infraredlight. In a further embodiment, the sensor may operate mechanically,capacitively, thermally, pneumatically or hydraulically.

In a still further embodiment, the sensor may emit an electric signal,which is transmitted to a control device, which is operative to put theequipment in the filling condition. The control device may be arrangedto relieve an over-pressure prevailing in the reservoir before filling.

In a yet further embodiment, the control device may be arranged to emita warning signal if the filling condition or the filling action prevailsfor more than a predetermined time period. Moreover, the control devicemay be arranged to terminate the filling condition if the fillingcondition or the filling action prevails for more than a predeterminedtime period.

In still a further embodiment the system may alternatively oradditionally have a second sensor device arranged adjacent the port forsensing when a filling vessel is inserted in the port, and thus fordetecting a filling action of the port. The second sensor device may bea sensor arranged at one side of the port and a detector arranged at anopposite side of the port. The sensor may be arranged to emit a signaluntil a fill vessel adapter is inserted in the port. Alternatively, afill vessel insertable into the port may comprise a sensor detectableunit for detection by the second sensor device upon insertion of thefill vessel into the port.

According to a further aspect of the invention, a method is provided forproviding safety for a breathing apparatus for delivery of an anestheticagent having an anesthetic agent vaporizer comprising a reservoir forcontaining a liquid anesthetic agent and a port for filling thereservoir with the liquid anesthetic agent, and a sensor device, whereinhe method comprises sensing a filling action of the port with the sensordevice.

In an embodiment the method may comprise arranging the breathingapparatus for delivery of an anesthetic agent having an anesthetic agentvaporizer into a filling condition upon sensing the filling action ofthe port.

According to a yet further aspect of the invention, a computer programis provided for providing safety for a breathing apparatus for deliveryof an anesthetic agent having an anesthetic agent vaporizer comprising areservoir for containing a liquid anesthetic agent and a port forfilling the reservoir with the liquid anesthetic agent, and a sensordevice, wherein the computer program for processing by a computercomprises a code segment for sensing a filling action of the port withthe sensor device.

According to another aspect of the invention, a signal for providingsafety for a breathing apparatus for delivery of an anesthetic agenthaving an anesthetic agent vaporizer comprising a reservoir forcontaining a liquid anesthetic agent and a port for filling thereservoir, the signal being generated by a sensor device for sensing afilling action of the port, the signal enabling arranging the breathingapparatus for delivery of an anesthetic agent having an anesthetic agentvaporizer into a filling condition.

Further embodiments of the invention are defined in the dependentclaims.

Some embodiments of the invention provide for increased patient safetyby providing safely continuous delivery of a medical agent even atperiods of refilling an anesthetic agent vaporizer, comprised in abreathing apparatus for delivery of an anesthetic agent, from which theanesthetic agent is delivered to the patient, e.g. by vaporizing theliquid anesthetic agent and adding it to breathing gases, for instanceby injecting the liquid anesthetic agent into a flow of breathing gas.

Some embodiments of the invention also provide for reduced possibilityof incidents during refilling the anesthetic agent vaporizer, comprisedin a breathing apparatus for delivery of anesthetic agents.

Some embodiments provide for increased operational safety of a vaporizerhaving a pressurized receptacle for a liquid anesthetic agent, byensuring a non-pressurized state of the receptacle containing the liquidanesthetic agent during a filling action of the receptacle with liquidanesthetic agent. The filling action may comprise filling or refillingthe receptacle.

Some embodiments of the invention also provide for reduced possibilityof contaminating the medical agent comprised in the breathing apparatusfor delivery of an anesthetic agent.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic block diagram of an anesthetic vaporizerrepresenting an embodiment of the present invention.

FIG. 2 is a sectional view of an anesthetic vaporizer having a safetysystem according to an embodiment of the invention.

FIG. 3 is an elevated perspective view of the anesthetic vaporizer ofFIG. 2 with a lid shown in FIG. 4 removed, revealing a refill port.

FIG. 4 is a bottom view of the lid comprised in the embodiment of FIG.2.

FIG. 5 is an exploded side view of the an anesthetic vaporizer of FIG. 2and the lid of FIG. 4.

FIG. 6 is a schematic block diagram of another comprising an embodimentof the invention.

FIG. 7 is a schematic block diagram of another anesthetic vaporizer inan embodiment of the invention.

FIG. 8 is a flowchart illustrating a method according to an embodimentof the invention.

FIG. 9 is a schematic illustration of a computer program according tothe invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Specific embodiments of the invention will now be described withreference to the accompanying drawings. This invention may, however, beembodied in many different forms and should not be construed as limitedto the embodiments set forth herein; rather, these embodiments areprovided so that this disclosure will be thorough and complete, and willfully convey the scope of the invention to those skilled in the art. Theterminology used in the detailed description of the embodimentsillustrated in the accompanying drawings is not intended to be limitingof the invention. In the drawings, like numbers refer to like elements.

The following description focuses on an embodiment of the presentinvention applicable to an anesthetic vaporizer. However, it will beappreciated that the invention is not limited to this application butmay be applied to many other medical liquid delivery systems.

FIG. 1 is a schematic block diagram of an anesthetic vaporizer 100 in anembodiment of the present invention. In use the anesthetic vaporizer isa component of a breathing apparatus for delivery of anesthetic agents.The anesthetic vaporizer 100 has a receptacle 107 for receiving a liquidanesthetic agent 106 via filling valve 101. A level sensor 102 measuresa current filling level of the receptacle 107 with liquid. A float 105prevents the pressurized liquid anesthetic agent 106 from becomingsaturated with gas. Via a filter 103 and a pressure sensor 104 thepressure inside the receptacle may be measured. The liquid anestheticagent 106 may be transported, when the receptacle 107 is pressurized,via a filter 108, and a safety valve 109 from the receptacle 107 to aninjector valve 111 into a chamber 112. A further pressure sensor 110 isprovided in the line connecting the receptacle 107 with the injectorvalve 111. The chamber 112 receives a flow of gas via an input port 113.The flow of gas thus may be provided with a varying degree of vaporizedanesthetic agent and leave the anesthetic vaporizer via an exit port114.

A protecting member, here in form of a lid 90, is provided covering theentry port to the filling valve 101. A sensor is provided for detectingthe position of the lid 90 relative the entry port 101.

FIG. 2 is a sectional view of an anesthetic vaporizer corresponding tothe vaporizer schematically shown in FIG. 1. The receptacle 107 isprovided with a refill port 18, which can be of the type disclosed in WO2005/056093 of the same applicant as the present application, thetechnical contents of which is incorporated in its entirety in thepresent specification by reference. Alternatively to the illustrated anddescribed filling port 18, other units, assemblies or arrangementsdevised for refilling an anesthetic vaporizer with liquid anestheticagent from a container, which are known to the skilled person, may beimplemented in other embodiments.

Basically, this refill port 18 has a filling assembly arranged in therefill port 18 and a valve system having a filling valve 101. Acontainer, such as bottle, containing a medical liquid is provided withan adapter fitting in the refill port 18. When the bottle with theadapter is inserted in the refill port, the valve system is opened.Then, a further valve system in the adapter is opened and a fluid pathis formed for permitting communication with the inner of receptacle 107.The liquid thus is allowed to flow to the inner of the receptacle 107,replacing the liquid in the container with gas from the inner ofreceptacle 107.

A mentioned above, it is important that the receptacle 107 is notpressurized during this refill procedure.

In order to protect the port 18 from being contaminated by dust anddebris during use, the port 18 is normally closed by a protectingmember, in the embodiment shown in FIG. 1 in the form of lid 90. Such aprotecting member can be of any suitable type, for example a screw capfor closing the port 18 in a gas-tight manner. In embodiments theprotecting member may be a wall closing the entrance to the port 18without sealing it in a gas-tight manner. The protecting member alsoprevents unintended operation of the port and the valve system in theport.

The protecting member is removable or displaceable in order to exposethe port 18. The protecting member may be rotatable around a shaft.Alternatively or additionally, the protecting member may be linearlydisplaceable as shown in FIG. 2 by arrow 150, which shows the port 18provided with a lid 90. The lid 90 is arranged in a groove 71 of theanesthetic vaporizer. The lid 90 is, by means of a handle 72, moveablebetween a first position, shown in solid lines and closing the entranceof port 18, and a second position shown in broken lines and exposing theopening 18 so that a bottle can be inserted in the port.

The lid 90 is provided with an indication in the form of a reflectingplate 93 arranged on the inner thereof. A sensor 74, for example in theform of a reading fork having a light source and a detector, is arrangedin a position opposite to a reflecting plate when the lid 90 is in itsclosed position, as shown in FIG. 2.

When the reflecting plate 93 is positioned opposite to the sensor 74,the light from the light source, such as a light emitting diode LED, isreflected by the reflecting plate 93 toward the detector, whichgenerates an output signal. This output signal may be provided to acontrol device.

The function of a control device, or a separate control circuit e.g. ofan anesthesia machine in which the vaporizer 100 is installed, is nowdescribed in more detail. The control device may have a control program,which upon receipt of a signal from the sensor 74 performs one orseveral of the following operations. As the sensor 74 indicates that theport 18 is at least partly covered by the lid 90 when a reflection basedsignal is received, the receptacle 107 may be pressurized and anestheticagent may be delivered therefrom.

In this case, the lid 90 is displaced transversally in order to reveal(expose) the port 18, whereupon sensor 74 no longer detects thereflection signal, thus indicating a filling action to the control unit.In this case the filling action is indicated by opening the lid 90 anddetecting that the lid 90 is opened. Upon detecting the filling action,the receptacle 107 is now automatically de-pressurized via a suitablevalve, e.g. until the pressure sensor 104 indicates that atmosphericpressure is present in the inner of receptacle 107. The anestheticvaporizer is now in a filling condition.

In other embodiments the filling condition of an anesthetic vaporizermay be accomplished in other ways than de-pressurizing the anestheticvaporizer. For instance, during operation of the anesthetic breathingapparatus, metering from the anesthetic vaporizer may be interrupted,e.g. by suitable electronical or mechanical switching action of theanesthetic vaporizer. The anesthetic vaporizer may be taken completelyor at least partly out of operation for establishing a filling conditionthereof. For instance a gas flow through the vaporizer may be stopped,decreased, or diverted into other suitable channels in the anestheticbreathing apparatus. Alternatively or in addition, and depending on thedesign of the anesthetic vaporizer and the anesthetic breathingapparatus, a fresh gas flow through the anesthetic vaporizer may bestopped or decreased, or a bypass of the fresh gas flow passing thevaporizer towards a breathing circle may be activated.

When the anesthetic vaporizer is in a filling condition, anestheticagent may be replenished via port 18 and filling valve 101 withoutpossibility of spillage by inserting a filling container into port 18.

When the bottle is removed and the lid 90 is returned to its closedposition, the signal of sensor 74 re-appears. Thus the filling action isterminated and an indication of a filling action by the sensor ceases.Then, the control device can be arranged to allow pressurization ofreceptacle 107 in order to place the equipment in an operatingcondition, after being refilled.

The lid 90 may be arranged to be moved aside when the bottle providedwith the adapter is inserted into the port 18, for example by means of acam surface (not shown).

FIG. 3 is a perspective view of a part 80 of the anesthetic vaporizer100 equipment comprising an opening 81 forming the port 18. Moreover,there is provided a recess 82 for enclosing the sensor 74 and a hole 83for an attachment screw. Moreover, the part 80 comprises grooves 84, 85forming seats for rails of the lid.

FIG. 4 is a bottom view of the lid 90. The lid 90 is provided with rails91, 92 mating with the grooves 84, 85 in the part 80. Moreover, areflecting plate 93 is arranged at the bottom side of the lid 90.

FIG. 5 is a side view of the part 80 with the lid 90 lifted up. In ahome position, the lid is arranged as shown by arrows 94, 95, so thatthe lid 90 covers the opening 81. Thus, dust and debris cannot enter theport 18 during normal use. Moreover, the port 18 is not accessible bymistake. Thus, the port is protected from unintended operation of thevalve system therein.

In the home position, the reflecting plate 93 is positioned opposite theopening 82, which houses the sensor 74. Thus, the sensor 74 emits asignal when the lid is in its home position, at least covering the port18.

When the anesthetic vaporizer is to be refilled with liquid anestheticagent, the lid is pushed aside to the left in FIG. 5 and a bottlecontaining anesthetic agent is inserted into the opening 81. Then, thereflecting plate 93 will no longer be positioned opposite the sensor 74and the sensor will no longer emit a signal. The ceasing of the signalwill influence upon the control device to perform actions, for exampleas indicated above.

In a further embodiment, the breathing apparatus for delivery of ananesthetic agent having an anesthetic agent vaporizer may also inaddition or alternatively include a second sensor 78, see FIG. 6, whichdetects when a filling vessel is inserted in the port 18. The secondsensor emits a signal on a line 79. The sensor 78 may be an opticalsensor that comprises a light source, such as a LED, arranged at oneside of the port 18 and a detector arranged at the other side of theport. Thus, the sensor 78 normally emits a signal on line 79. When arefill adapter is inserted in the port 18, the light ray is broken andthe signal from the sensor 78 ceases on line 79. Line 79 may beconnected to the control device mentioned above.

FIG. 7 schematically shows an anesthetic agent vaporizer comprising anembodiment of the present invention. The equipment comprises a primaryreservoir 1 containing a medical liquid 2, such as an anesthetic agent,to be delivered to a patient, for example in a breathing gas stream. Thespace 4 above the medical liquid level is via a port 3 connected to asource for gas under pressure via a line 12 and a controllable firstvalve 10. The space 4 can also be connected to atmospheric pressure by acontrollable second valve 14 and a line 16. The line 16 can be connectedto a means for taking care of the gas expelled from the space 4, forexample for reuse or for making the gas harmless. The other embodimentsmay have similar arrangements.

In contrast to the above described embodiments, an outlet 6 from thefirst reservoir 1 is via a controllable third valve 8 and a line 9connected to a secondary reservoir 22. An outlet 25 from the secondaryreservoir is via a controllable fourth valve 26 and a line 28 connectedto a medical liquid consuming device. A pressure-maintaining member 24is arranged inside the secondary vessel. The purpose of the secondaryreservoir 22 is to provide uninterrupted delivery of an anesthetic agentduring replenishment of the first reservoir 1.

The pressure inside the secondary reservoir 22 is measured by a sensor30 via a line 20. The sensor may also measure the pressure in space 4via a line 46 shown in broken lines. The pressure signal from the sensor30 is sent to a control device 40 having a calculating unit 42. Thecontrol device 40 controls the four valves 10, 14, 8 and 26 via lines48, 50, 32 and 34, respectively. The valves 10, 14, 8 and 26 arecontrolled by an algorithm processed in the calculating unit 42. Thecontrol device 40 may emit signals at a line 44, such as alarm signalsat error conditions.

The operation of the secondary reservoir 22 and the control device 40 isnot the object of the present invention and will not be furtherdescribed, but reference is made to WO 2007/006348 of the same applicantas the present invention, the technical contents of which isincorporated in its entirety in the present specification by reference.

The primary reservoir 1 is provided with a refill port 18, which may beof the type disclosed in WO 2005/056093.

In order to protect the port 18 from being contaminated by dust anddebris during use, the port 18 is normally closed by a protecting member60 according to the embodiment shown in FIG. 7. Such a protecting membercan be of any suitable type, for example a screw cap for closing theport 18 in a gas-tight manner. The protecting member may be a wallclosing the entrance to the port 18 without sealing it in a gas-tightmanner. The protecting member also prevents unintended operation of theport and the valve system in the port. The protecting member 60 isremovable or displaceable in order to expose the port 18. It may berotatable around a shaft 61 as indicated by a broken line in FIG. 1.

Alternatively or additionally, the protecting member may be linearlydisplaceable as shown in FIG. 6, which discloses the port 18 providedwith a lid 70. The lid 70 is arranged in a groove 71 of the anestheticvaporizer. The lid 70 is, by means of a handle 72, moveable between afirst position, shown in solid lines and closing the entrance of port18, and a second position shown in broken lines and exposing the opening18 so that a bottle can be inserted in the port.

The lid 70 is provided with an indication in the form of a reflectingplate 73 arranged below the handle 72. In this embodiment, sensor 74 isarranged in a position opposite to the reflecting plate 73 when the lidis in its opened position, as shown in FIG. 6 by broken lines.

When the reflecting plate 73 is moved to be positioned opposite to thesensor 74, the light from the light source, such as a light emittingdiode LED, is reflected by the reflecting plate 73 towards the detector,which generates an output signal on a line 75. The line 75 may beconnected to the control device 40 in the embodiment of FIG. 1, or maybe connected to a separate control circuit.

If the line 75 is connected to the control device 40, the control device40 may have a control program, which upon receipt of a signal from thesensor 74 performs one or several of the following operations:

1) valve 8 is closed via line 32 in order to isolate the secondaryreservoir 22 from the first reservoir 1; and

2) valve 10 is closed via line 48 and valve 14 is opened via line 50 inorder to reduce the pressure in the space 4 to atmospheric pressure.

When the bottle is removed and the lid 70 is returned to its closedposition, the signal on line 75 disappears. Then, the control device 40can be arranged to reverse the above-mentioned operations of the valves,in order to place the equipment in an operating condition, after beingrefilled.

As an extra safety measure, the port 18 may be provided with a fifthvalve 76 controllable via a line 77. The control device 40 may bearranged to open the fifth valve 76 to allow medical liquid from aconnected bottle to enter the primary reservoir and gas to enter thebottle from the reservoir replacing the liquid. In this way, the valve76 is opened when the pressure in the space 4 is close to theatmospheric pressure, as sensed by the pressure sensor 30 via line 46.

Hence, refilling of the primary reservoir is effectively prevented whenthe latter is pressurized. Spillage of medical liquid is effectivelyprevented and safety of the device is increased.

The fifth valve 76 may be a pressure-controlled valve, which is closedwhen the pressure over the valve, and thus, the absolute pressure in thespace 4, is above a predetermined value. When the pressure in space 4 isreduced by opening the second valve 14, the fifth valve 76 willautomatically open, when the pressure is reduced below the predeterminedpressure.

When the anesthetic vaporizer is to be refilled with anesthetic agent,the lid 70 is pushed aside to the left in FIG. 6 and a bottle containinganesthetic agent is inserted into the opening 81. Then, the reflectingplate 73 will be positioned opposite the sensor 74 and the sensor willemit a signal. The signal will influence upon the control device 40 toperform actions, for example as indicated above, such as closing thefirst valve 10 and third valve 8 followed by opening the second valve 14in order to relieve pressure from chamber 1 and thus enable saferefilling of the reservoir 1 through the opening 81 and the port 18.

In addition, the control device 40 may be arranged to start a timer whenthe signal from the sensor 74 ceases. If the signal from the sensor 74is not present again before a predetermined time period, the controldevice 40 may emit a warning signal. This may be desired if a userleaves a refill bottle for too long time in the port 18, which might bethe case due to the human factor. The user may for instance bedistracted by an emergency clinical situation during refill and leavethe refill container unattended. The control device may be arranged toemit a warning signal in such cases.

Alternatively or additionally to emitting a warning signal, the controldevice 40 may be arranged, after the predetermined time period haselapsed, to close the fourth valve 76 to disconnect the bottle from theprimary reservoir, close the second valve 16 and open the first valve 10to pressurize the primary reservoir and finally open the third valve 8in order to automatically restore normal operation of the anestheticvaporizer. In order to refill the primary reservoir again, the bottlehas to be removed and the lid 70 closed to the home position, whereupona new filling procedure may take place.

The anesthetic vaporizer can also include a second sensor 78, see FIG.6, which detects when a refilling vessel is inserted in the port 18, asexplained above. The second sensor emits a signal on line 79. Inaddition to the above described arrangement of the second sensor 78, oralternatively, for instance an adapter or neck of a refill vessel maycomprise a sensor detectable unit, such as a reflecting part detectableby an optical sensor, a magnet detectable by a Hall sensor, transponderreturning a signal on a request signal, etc. The sensor detectable unitallows reliable detection thereof when inserted into port 18. Line 79may be connected to the control device 40 or other control devices.

The anesthetic agent may be one of Halothane, Isoflurane, Sevoflurane,Enflurane, Desflurane, or other medical agents suitable for delivery ananesthetic vaporizer.

The refill condition may also be a filling condition, when filling forthe first time. The filling action may be a refilling condition whenreplenishing the receptacle of an anesthetic vaporizer.

The sensors may be part of an anesthetic vaporizer itself or may be partof a breathing apparatus in which the anesthetic vaporizer is to beoperated.

In the above-mentioned embodiments, the sensors comprise a light sourceand a light detector. However, each sensor may operate with other typesof radiation, such as any type of electromagnetic radiation, such asultraviolet or infrared light or microwaves. Alternatively, sound,ultrasound may be used. A magnet and a Hall-sensor, a magnetic diode, amagnetostrictive or magnetoresistive sensor, or a Reed contact wouldalso be possible to use. As an alternative capacitive sensors may beused. Also, temperature based sensors may be used, e.g. a Peltierelement, a temperature controlled resistor, or thermoelements may detecta defined temperature provided by a units such as a heat generatingresistor, a Peltier element etc. Also, an oscillator, such as a radiofrequency oscillator, may change its frequency in dependence of afilling action. Mechanical sensors may be based on strain detection,piezoelectric pressure detecting sensors or accelerometers detecting achange of position of an element of an anesthetic breathing apparatusindicating a filling action. Furthermore, combinations of such sensorprinciples may be implemented suitably.

Still alternatively, the sensor may be a mechanical sensor, such as anelectric switch or a mechanical rod, or a pneumatic or hydraulic sensor.In this embodiment, the sensor may directly influence upon and actuatethe respective valves 12, 16 and 8 (and valve 76 if present).

The protection member may be moveable in a linear, rotational orpivoting movement.

FIG. 8 is a flowchart illustrating a method according to an embodimentof the invention. A method of providing safety for an anestheticvaporizer having a reservoir for containing a liquid anesthetic agentand a port for filling the reservoir with the liquid anesthetic agent,and a sensor device arranged adjacent the port. The method 200 includessensing (210) a filling action of the port with the sensor device. Themethod may include arranging (220) the anesthetic vaporizer into afilling condition upon sensing the filling action of the port.

FIG. 9 is a schematic illustration of a computer program according tothe invention. A computer program 300 for providing safety for ananesthetic vaporizer is shown. The anesthetic vaporizer comprises areservoir for containing a liquid anesthetic agent and a port forfilling the reservoir with the liquid anesthetic agent, and a sensordevice arranged adjacent the port. The computer program adapted forprocessing by a computer has a code segment 310 for sensing a fillingaction at the port with the sensor device. The computer program mayenable carrying out of a method according to above with reference toFIG. 8. The computer program may be embodied on a computer-readablemedium 320.

The invention can be implemented in any suitable form. The elements andcomponents of the embodiments according to the invention may bephysically, functionally, and logically implemented in any suitable way.Indeed, the functionality may be implemented in a single unit, in aplurality of units, or as part of other functional units.

The indefinite articles “a” and “an,” as used herein in thespecification and in the claims, unless clearly indicated to thecontrary, should be understood to mean “at least one.” The phrase“and/or,” as used herein in the specification and in the claims, shouldbe understood to mean “either or both” of the elements so conjoined,i.e., elements that are conjunctively present in some cases anddisjunctively present in other cases.

Although the present invention has been described above with referenceto specific embodiments, it is not intended to be limited to thespecific form set forth herein. Rather, the invention is limited only bythe accompanying claims and, other embodiments than the specific aboveare equally possible within the scope of these appended claims.

I claim as my invention:
 1. An anesthetic vaporizer for delivery ofpressurized anesthetic agent to a breathing apparatus comprising: areservoir containing a liquid anesthetic agent in an interior of saidreservoir; a filling sensor; said reservoir comprising a normally closedrefilling port for receiving a filling vessel that, when opened, allowsrefilling of the reservoir with said liquid anesthetic agent; saidfilling sensor is arranged for sensing a filling at the port andthereupon emit an output signal, a computerized control unit configuredto receive said output signal and upon receiving said output signalautomatically relieve an overpressure in said anesthetic liquidreservoir, said filling sensor is further arranged for sensing when thefilling at the port is terminated and thereupon emit a second outputsignal, and said computerized control unit is configured to receive saidsecond output signal and upon receiving said second output signalallowing pressurization of said anesthetic liquid reservoir.
 2. Theanesthetic vaporizer of claim 1, wherein said port further comprises aprotection member that normally closes said port, and wherein saidfilling sensor detects a displacement of said protection member.
 3. Theanesthetic vaporizer of claim 2, wherein said protection member, whenclosing said port, is located in a home position, and wherein saidfilling sensor detects displacement of said protection member from saidhome position.
 4. The anesthetic vaporizer of claim 3, wherein saidfilling sensor is configured to emit said filling sensor signal as longas said protection member is in said home position and to cease to emitsaid output signal when said protection member is displaced from saidhome position.
 5. The anesthetic vaporizer of claim 2, wherein saidfilling sensor is configured to emit said filling sensor signal whensaid protection member is located in a position that opens said refillport.
 6. The anesthetic vaporizer of claim 5, wherein said protectionmember is a lid that is movable to open said port by executing amovement selected from the group consisting of a linear movement, arotational movement and a pivoting movement.
 7. The anesthetic vaporizerof claim 1, wherein said filling sensor is configured to detectinsertion of a filling vessel into said refill port.
 8. The anestheticvaporizer of claim 7, wherein said filling sensor comprises an emitterlocated at a side of said port that emits an emitter signal, and adetector located at an opposite side of said port that detects saidemitter signal, and wherein said filling sensor is configured to emitsaid filling sensor signal when a filling vessel blocks said emittersignal from being detected by said detector.
 9. The anesthetic vaporizerof claim 7, wherein said filling sensor comprises a detectable itemcarried by said filling vessel and a detector located at said refillport that detects said detectable item when said filling vessel isinserted into said refill port.
 10. The anesthetic vaporizer of claim 1,wherein said filling sensor is configured to employ radiation selectedfrom the group consisting of electromagnetic radiation, ultravioletradiation, visible light radiation, and infrared radiation.
 11. Theanesthetic vaporizer of claim 1, wherein said filling sensor comprises adevice selected from the group consisting of a mechanical sensor device,an electronic sensor device, a capacitive sensor device, a thermalsensor device, a magnetic sensor device, a pneumatic sensor device, ahydraulic sensor device, and combinations thereof.
 12. The anestheticvaporizer of claim 1, wherein said computerized control unit isconfigured to emit a warning signal when said filling condition or saidfilling occurs for longer than a predetermined time duration.
 13. Theanesthetic vaporizer according to claim 1 further comprising a levelsensor and said level sensor is arranged for measuring a current fillinglevel of the reservoir with liquid.
 14. A method for operating ananesthetic vaporizer recited in claim 1 comprising; detecting saidfilling by said filling sensor; transmitting said output signal to saidcomputerized control unit; automatically relieving said overpressure insaid liquid anesthesia reservoir by said computerized control unit uponreceiving said output signal; and preventing the opening of said fillingvalve until said overpressure in said liquid anesthetic reservoir hasbeen relieved.
 15. A computer program for providing safety at deliveryof pressurized anesthetic agent from an anesthetic vaporizer comprisinga reservoir for containing a liquid anesthetic agent in an interior ofsaid reservoir and a port for filling said reservoir with said liquidanesthetic agent, and a sensor device, said computer program forprocessing by a computer comprising a code segment for sensing a fillingat said port with said sensor device.